In short, you can not plug both XLR's and RCA plug into the XA60.5 simultaneously. If you plan to use the RCA plugs there must be a shorting bar between pins 1 and 3 on the XLR input connector. If you wish to use an XLR input the shorting bar must be removed. Reference the user manual. I have a X350.5 and it works the same way.
http://www.passlabs.com/pdfs/product%20manuals/xa60_5-om.pdf
http://www.passlabs.com/pdfs/product%20manuals/xa60_5-om.pdf